CMOS Full Form

Although abbreviations aren’t unique, and a single abbreviation could sometimes represent multiple full forms, some abbreviations commonly mean only one thing. Whenever you hear the abbreviation, only one thing comes to everybody’s mind without variation of ambiguity of any kind. Such is the abbreviation “CMOS.”

The full form of CMOS is a Complementary Metal-Oxide Semiconductor. CMOS is generally pronounced as “c-moss” for ease. Complementary Metal-Oxide Semiconductor is a popular technology and is used in the chipset of computers.

It is the building or basic block used to design an integrated circuit or a transistor. CMOS is generally used for applications where high-density transistors are required.

Complementary Metal Oxide Semiconductor

The Complementary Metal Oxide Semiconductor is named, so it consists of both NMOS (N-channel metal-oxide semiconductor) and a PMOS (Positive Channel Metal Oxide Semiconductor) transistor. MOS uses complementary pairs of n-type and p-type MOSFETs, which are symmetrical to carry out logical functions.

Following are the most useful characteristics that a Complementary Metal Oxide Semiconductor possesses.

• Providing high immunity to noise 
• Consuming less static power

Also, devices that use Complementary Metal Oxide semiconductors don’t lead to the creation of a huge amount of waste heat compared to other types of transistors- TTL. The TTL, i.e., the transistor logic, produces current even when the state isn’t changing. This current is called the standing current.

All the above-stated qualities of Complementary Metal Oxide Semiconductors permit CMOS to integrate a great density of logical functions. This made CMOS one of the most popular which was used in the VLSI chips.

Technical Details of CMOS

CMOS is a type of design for digital circuits. It is also a collection of processes used to implement circuits on IC. IC means Integrated chips or circuits. CMOS’s advantage over logic families that contain resistive loads is that it consumes less power.

The power consumption of NMOS logic is seven times more than that of CMOS logic.

And Complementary Metal Oxide Semiconductor consumes thousands of times less power than bipolar logic. CMOS circuits implement digital circuits and logic gates using N-type and p-type metal oxide semiconductor transistors. Also called MOSFETs.

In commercial CMOS products, billions of transistors of n-type and p-type are used to compose integrated circuits on a piece of silicon. This piece is shaped like a rectangle and has an area between 10 mm² – 400 mm².MOSFETs in Enhancement-mode are used in Complementary Metal Oxide semiconductors.

History of CMOS

During the late 1960s, RCA commercialized the Complementary Metal Oxide Semiconductors. 

RCA developed CMOS for the following purposes.

• To design Integrated Circuits 

• 1965- To develop a computer for the Air force

• 1968- CMOS SRAM memory chip of 288- bit was developed
• 1968- integrated circuits of 4000-series were designed

In the American market, NMOS was dominant when CMOS was initially discovered. So, the semiconductor industries in America ignored CMOS Technology. NMOS was considered to be more powerful.

However, the Japanese semiconductor industry instantly adopted CMOS technology. This was because CMOS came with advantages such as less power consumption. Japanese manufacturers further developed the CMOS Technology, and hence Japanese semiconductor industries got popular in the global market.

During the 1970’s first few years, PMOS processes were widely used. During the later years of the 1970s, NMOS Technology seemed to dominate PMOS Technology. The CMOS technology began rising in the 1980s.

Hitachi discovered 160 nm CMOS during the mid-1990s. Then Mitsubishi manufactured 150 nm CMOS a year later. Later Samsung electronics came up with 190 nanometres CMOS.

Now CMOS is used in integrated chips off most computers and VLSI and LSI devices.

However, Complementary Metal Oxide Semiconductor Technology is slowly being replaced. This is happening due to the rise of non-planar FinFET technology. On-planar FinFET technology offers the ability to manufacture nodes of semiconductors less than 20 nanometres.

Power consumption by CMOS

CMOS logic’s power dissipation is a lot less compared to NMOS circuits. This is because power is dissipated by CMOS circuits while switching only.

On the contrary, power is dissipated by the NMOS circuit all the time when a transistor is on. Because through n-type network and load resistors, a current path exists between Vss and Vdd.

Static CMOS is quite efficient in power, and no power is dissipated in an idle state.

Range of CMOS temperature

Most of the CMOS devices work between the temperature of −55 °C to +125 °C. 

Overclocked AMD Phenom II processors 

can function near temperatures of 40k. This is achieved by combining liquid helium cooling and liquid nitrogen.

CMOS devices with Silicon Carbide work at 500°C as well. It has been tested for about a year.

Conclusion

CMOS has only one commonly known full form. That is a Complementary Metal Oxide Semiconductor. CMOS is used as a transistor while constructing Integrated Circuits for chipsets of computers. CMOS is used in devices where high-density transistors are required. CMOS uses both PMOS as well as NMOS types of transistors in combination.

CMOS offers high immunity to noise, and the power consumption of CMOS is a lot less than other transistors. The CMOS devices include CMOS inverter, CMOS NAND gate, etc. Most CMOS devices work in a temperature from -5 to as high as +125. However, CMOS is being replaced by non-planar FinFET technology.